Hi, Not a full review of fusion, but just some (slightly confused...apologies) thoughts. I started to look into fusion to try to understand what it is exactly. I have an idea what it might be about so I decided to look in the examples directory. Is there only one example? I am surprised. is that due to lack of time? There also doesnt seem to be much in way of examples in the documentation. Would it be possible to have a simple definition of what a view is, as it doesnt seem to be defined anywhere, or is it? How expensive is it to construct a view at runtime. Is it likely that the view is easy for the compiler to optimise (IOW so that the actual code references the original sequence). I am kind of interested in this library ( though unsure if it can help exactly with my problems), I have a matrix which is in fact a tuple of tuples and I'm wondering if fusion could help me in iterating over it. For example currently I am writing out each co_factor function explicitly ( of which there are 16) though I presume it would be possible to find the generic algorithm, so writing one function: // cofactor function of 3D homogeneous matrix // constrained to cofactor(0,0) using enable_if template<int R, int C> typename boost::enable_if_c< R == 0 && C ==0, value_type >::type cofactor()const { value_type t = ( this->at<1,1>() * ( this->at<2,2>() * this->at<3,3>() - this->at<2,3>() * this->at<3,2>()) - this->at<1,2>() * ( this->at<2,1>() * this->at<3,3>() - this->at<2,3>() * this->at<3,1>()) + this->at<1,3>() * ( this->at<2,1>() * this->at<3,2>() - this->at<2,2>() * this->at<3,1>()) ); return t; } There probably isnt enough detail here to provide a solution to this particular problem, but does it look like the sort of problem that fusion could help with?. regards Andy Little